Interpretive Summary: Chronic psychological stress has been linked to poor food choice and abnormal eating behaviors. The neurological basis for this stress-eating connection is not established. We used functional brain imaging (fMRI) to study the influence of self-reported chronic stress on the brain’s response to high calorie and low calorie food cues (pictures). Women reporting higher chronic stress and viewing high calorie foods (compared to non-food and low calorie pictures) had exaggerated activity in brain regions associated with reward, emotional, and habit-based food intake. Furthermore, high stress women had reduced activity in brain regions that mediate self-control and decision making. We also found on separate lab visit days that the high chronic stress women ate more high fat-sweet food from a voluntary snack food buffet and altered cortisol concentrations previously linked to high chronic stress. These results suggest that persistent stress exposure may alter the brain’s response to food in ways that predispose individuals to poor eating habits which, if sustained, may increase risk for obesity.

Technical Abstract:
Exaggerated reactivity to food cues involving calorically-dense foods may significantly contribute to food consumption beyond caloric need Exaggerated reactivity to food cues involving calorically-dense foods may significantly contribute to food consumption beyond caloric need. Chronic stress, which can induce palatable “comfort” food consumption, may trigger or reinforce neural pathways leading to stronger reactions to highly rewarding foods. We implemented functional magnetic resonance imaging (fMRI) to assess whether chronic stress influences activation in reward, motivation and executive brain regions in response to pictures of high calorie and low calorie foods in thirty women. On separate lab visits, we also assessed food intake from a snack food buffet and circulating cortisol. In women reporting higher chronic stress (HCS), pictures of high calorie foods elicited exaggerated activity in regions of the brain involving reward, motivation, and habitual decision-making. In response to pictures of high calorie food, higher chronic stress was also associated with significant deactivation in frontal regions (BA10; BA46) linked to strategic planning and emotional control. In functional connectivity analysis, HCS strengthened connectivity between amygdala and the putamen, while LCS enhanced connectivity between amygdala and the anterior cingulate and anterior prefrontal cortex (BA10). A hypocortisolemic signature and more consumption of high calorie foods from the snack buffet were observed in the HCS group. These results suggest that persistent stress exposure may alter the brain’s response to food in ways that predispose individuals to poor eating habits which, if sustained, may increase risk for obesity.